Sibelius

At a Glance

If you're a professional composer, arranger, or copyist--or
anyone else looking for the absolute best in notation
software--Sibelius is one of the two programs you should be kicking
the tires of (the other being rival MakeMusic's Finale). Sibelius
offers comprehensive notation features including the advanced
notation required by modern composers, plus music OCR via the
bundled PhotoScore Lite, .wav to MIDI conversion with AudioScore
Lite, and a complete collection of orchestral sounds.

Sibelius is easier for beginners to get up to speed with than
Finale, though it's still easy to get lost in the labyrinth of
features and can't match Notion in
the interface department. Pianists and guitarists will appreciate
the ability to enter notes via the onscreen keyboard and
fretboard.

Note: This link takes you to the vendor's site,
where you can download the software. As of this writing, the
current demo is v6.1 and does not allow you to save your work;
vendor Avid has already released a full version of Sibelius
6.2.